Alfa-Romeo uses the arms of Milan: Per pale argent a cross gules, and
[argent]azure a serpent ondoyant in pale [azure]vert crowned with a ducal
crown or and vorant a child gules. (The tinctures are modified from
the original coat). The dexter coat is that of the city, the sinister coat
is that of the duchy.

There is a
historical description of the Alfa-Romeo logo (in German). The present version
dates from 1972. Until 1946 the legend around the shield included two Savoy knots.

Austin-Morris

The Austin and Morris cars produced by British Motor Corporation (later
Leyland Motor Corporation or Leykor) carried coats of arms.
The Morrises carried the municipal arms of Oxford, showing a red ox above
wavy barrulets representing water. These, like the VW badges, also became
stylised. They most likely go back to the early models produced by Lord
Nuffield's factories.

Cadillac uses as its emblem the arms of Antoine de La Mothe, seigneur
de Cadillac, born in Gascony on March 5, 1658 of minor nobility. He founded
Detroit in 1701, and was governor of Louisiana. His arms were: Quarterly,
1 and 4: Or a fess between three martlets sable, 2 and 3: quarterly gules
and argent three bars azure. The count's coronet is fanciful, as was
often the case in 17th and 18th c. France.

Chrysler/Dodge

Dodge motorcars from Chrysler carried a Dodge coat of arms (barry of
six, or and sable, a pale gules overall). It's interesting that whereas
some Dodge families include (on the pale) a canting breast producing
droplets of milk (a dug), the car badge omits this, possibly out of Puritan
considerations.

The Ferrari emblem is a horse saliant sable on a "canari yellow" field.
It derives from the arms of the Baracca family (Argent a horse saliant
beneath a star gules and a chief of the Empire). The circumstances
surrounding the adoption of this logo by Enzo Ferrari are told
by him.

Ford/Taunus

German Ford cars made in the 1960s under the name Ford Taunus carried
the arms of Cologne.

The Porsche logo uses the arms of Wuerttemberg
with the arms of the city
of Stuttgart over-all. The blazon is: Quarterly or three stag's
horns fessways in pale sable, and barry of four sable and gules; overall
Or a horse saliant sable.

(This section thanks to Mats Persson)The logo of SAAB consists of the crowned griffin from the arms of
the province of Skåne
(Scania) in southern Sweden: Or, a griffin gules crowned azur. This is
the official coat of arms of Skåne since 1660 and has its origin
in the medieval arms of the city of Malmö.
The reason why SAAB adopted it as its logo is that the original SAAB company
(which produced small cars and aeroplanes) merged in 1969 with the truck
manufacturer Scania-Vabis which in turn consisted of two companies, originated
in Malmoe and in Södertälje, respectively.

Volkswagen

The arms of Wolfsburg appeared for a couple of
decades on the steering wheels of Volkswagens, initially in full-colour
enamel in an old-fashioned style, but later on highly stylised and in
incorrect colours.